This invention relates to the preparation of high temperature superconductors, and is particularly directed to a low temperature process for the preparation of high temperature superconductors such as yttrium barium copper oxide.
High temperature superconducting materials are generally those materials having superconductivity at temperatures higher than 30.degree. K., usually in the T.sub.c range of 95.degree.-130.degree. K.
Recently the high temperature synthesis of yttrium barium copper oxide, YBa.sub.2 Cu.sub.3 O.sub.8-x, a high temperature superconductor material, has been prepared by the high-temperature solid-state reactions of Y.sub.2 O.sub.3, BaCO.sub.3 and CuO in stoichiometric quantities corresponding to the desired metal mode ratio of 1:2:3 respectively. The reactants are ground together using an agate mortar and pestle and heated at 950.degree. C. for 12 hours in air. This method requires pure starting materials and high temperatures, and the very crystalline highly sintered product cannot be readily made into useful devices. Additionally, scale-up of the reaction presents difficulties.
It is one object of the invention to prepare high temperature superconductors such as yttrium barium copper oxide by an improved procedure.
Another object is to provide a procedure for preparing high temperature superconductors using substantially lower temperatures than heretofore employed.
Still another object is the provision of a relatively simple procedure for producing high temperature superconductors employing commercially available starting materials and which can be incorporated into useful devices.
These and many other objects, advantages, and features are described in the drawings and detailed description that follows.